The present invention relates to a method for the manufacture of die-forged or die-stamped workpieces, preferably hand tools, in which, after the stamping or forging process, the burr on the rough workpiece is removed, and the rough workpiece is machined at least at those areas important for the functioning of the workpiece, and is heat-treated to achieve a structural change in the material.
In the known methods for the manufacture of die-forged or die-stamped workpieces a blank is manufactured first, for example, by cutting a piece from a plate or stamping a piece from a metal sheet. This blank is subsequently die-forged or die-stamped, whereby a burr is inevitably created at the junction plane of the top and bottom part of the die. The resulting burr at the rough stamped or the rough forged piece is then removed by a cutting tool in a press. The rough stamped or forged piece is then heat-treated, for example, by normalizing or annealing, and sandblasted afterwards. Since the burr created by the die cannot be completely removed by the cutting tool, the burr must be ground by a special grinding machine, before the areas important for the functioning of the workpiece, for example, the face of the spanner clearance on hand tools, are machined by milling or reaming. Upon the completion of this machining process another heat-treatment is performed in order to harden and temper the workpiece, followed by an adjustment process to straighten the workpiece, which is warped due to the previous heat-treatments. Despite the straightening process, the workpiece must be subsequently machined at the areas important for the functioning of the workpiece, for example, by milling, reaming or grinding. Finally it must be sandblasted again, before it may be finished by chrome plating or other surface-treatments.
The abovementioned methods require a multitude of different manufacturing steps in order to finish a rough stamped or forged piece.
It is therefore an object of the present invention to provide an improved method for the manufacture of die-forged or die-stamped workpieces, in which fewer manufacturing steps are required so that a faster and more economical manufacture of the workpiece is achieved.